4 HENRY A. BOWLAND 



additions to and developments of his first magnetic research. There 

 was also a paper in which he discussed Kohlrausch's determination of 

 the absolute value of the Siemens unit of electrical resistance, fore- 

 shadowing the important part which he was to play in later years in the 

 final establishment of standards for electrical measurement. 



In 1875, having been appointed to the professorship of physics in 

 the Johns Hopkins University, the faculty of which was just then 

 being organized, he visited Europe, spending the better part of a year 

 in the various centres of scientific activity, including several months at 

 Berlin in the laboratory of the greatest Continental physicist of his 

 time, von Helmholtz. While there he made a very important investi- 

 gation of the magnetic effect of moving electrostatic charges, a question 

 of first rank in theoretical interest and significance. His manner of 

 planning and executing this research made a marked impression upon 

 the distinguished Director of the laboratory in which it was done, and, 

 indeed, upon all who had any relations with Eowland during its pro- 

 gress. He found what von Helmholtz himself had sought for in vain, 

 and when the investigation was finished in a time which seemed incred- 

 ibly short to his more deliberate and painstaking associates, the Director 

 not only paid it the compliment of an immediate presentation to the 

 Berlin Academy, but voluntarily met all expenses connected with its 

 execution. 



The publication of this research added much to Eowland's rapidly- 

 growing reputation, and because of that fact, as well as on account of 

 its intrinsic value, it is important to note that his conclusions have 

 been held in question, with varying degrees of confidence, from the day 

 of their announcement to the present. The experiment is one of great 

 difficulty and the effect to be looked for is very small and therefore 

 likely to be lost among unrecognized instrumental and observational 

 errors. It was characteristic of Eowland's genius that with compara- 

 tively crude apparatus he got at the truth of the thing in the very start. 

 Others who have attempted to repeat his work have not been uniformly 

 successful, some of them obtaining a wholly negative result, even when 

 using apparatus apparently more complete and effective than that first 

 employed by Eowland. Such was the experience of Lecher in 1884, 

 but in 1888 Eoentgen confirmed Eowland's experiments, detecting the 

 existence of the alleged effect. The result seeming to be in doubt, 

 Eowland himself, assisted by Hutchinson, in 1889 took it up again, 

 using essentially his original method but employing more elaborate and 

 sensitive apparatus. They not only confirmed the early experiments, 



